1 /*****************************************************************************
2 * RRDtool 1.3.1 Copyright by Tobi Oetiker, 1997-2008
3 *****************************************************************************
4 * rrd_open.c Open an RRD File
5 *****************************************************************************
7 *****************************************************************************/
13 /* DEBUG 2 prints information obtained via mincore(2) */
15 /* do not calculate exact madvise hints but assume 1 page for headers and
16 * set DONTNEED for the rest, which is assumed to be data */
17 /* Avoid calling madvise on areas that were already hinted. May be benefical if
18 * your syscalls are very slow */
21 /* the cast to void* is there to avoid this warning seen on ia64 with certain
22 versions of gcc: 'cast increases required alignment of target type'
24 #define __rrd_read(dst, dst_t, cnt) \
25 (dst) = (dst_t*)(void*) (data + offset); \
26 offset += sizeof(dst_t) * (cnt)
28 #define __rrd_read(dst, dst_t, cnt) \
29 if ((dst = malloc(sizeof(dst_t)*(cnt))) == NULL) { \
30 rrd_set_error(#dst " malloc"); \
31 goto out_nullify_head; \
33 offset += read (rrd_file->fd, dst, sizeof(dst_t)*(cnt))
36 /* get the address of the start of this page */
37 #if defined USE_MADVISE || defined HAVE_POSIX_FADVISE
39 #define PAGE_START(addr) ((addr)&(~(_page_size-1)))
43 /* Open a database file, return its header and an open filehandle,
44 * positioned to the first cdp in the first rra.
45 * In the error path of rrd_open, only rrd_free(&rrd) has to be called
46 * before returning an error. Do not call rrd_close upon failure of rrd_open.
50 const char *const file_name,
55 mode_t mode = S_IRUSR;
59 ssize_t _page_size = sysconf(_SC_PAGESIZE);
60 int mm_prot = PROT_READ, mm_flags = 0;
65 rrd_file_t *rrd_file = NULL;
66 off_t newfile_size = 0;
68 if (rdwr & RRD_CREAT) {
69 /* yes bad inline signaling alert, we are using the
70 floatcookie to pass the size in ... only used in resize */
71 newfile_size = (off_t) rrd->stat_head->float_cookie;
75 rrd_file = malloc(sizeof(rrd_file_t));
76 if (rrd_file == NULL) {
77 rrd_set_error("allocating rrd_file descriptor for '%s'", file_name);
80 memset(rrd_file, 0, sizeof(rrd_file_t));
83 if ((rdwr & (RRD_READONLY | RRD_READWRITE)) ==
84 (RRD_READONLY | RRD_READWRITE)) {
85 /* Both READONLY and READWRITE were given, which is invalid. */
86 rrd_set_error("in read/write request mask");
90 if (rdwr & RRD_READONLY) {
93 mm_flags = MAP_PRIVATE;
95 mm_flags |= MAP_NORESERVE; /* readonly, so no swap backing needed */
99 if (rdwr & RRD_READWRITE) {
103 mm_flags = MAP_SHARED;
104 mm_prot |= PROT_WRITE;
107 if (rdwr & RRD_CREAT) {
108 flags |= (O_CREAT | O_TRUNC);
111 if (rdwr & RRD_READAHEAD) {
113 mm_flags |= MAP_POPULATE; /* populate ptes and data */
115 #if defined MAP_NONBLOCK
116 mm_flags |= MAP_NONBLOCK; /* just populate ptes */
120 #if defined(_WIN32) && !defined(__CYGWIN__) && !defined(__CYGWIN32__)
124 if ((rrd_file->fd = open(file_name, flags, mode)) < 0) {
125 rrd_set_error("opening '%s': %s", file_name, rrd_strerror(errno));
129 /* Better try to avoid seeks as much as possible. stat may be heavy but
130 * many concurrent seeks are even worse. */
131 if (newfile_size == 0 && ((fstat(rrd_file->fd, &statb)) < 0)) {
132 rrd_set_error("fstat '%s': %s", file_name, rrd_strerror(errno));
135 if (newfile_size == 0) {
136 rrd_file->file_len = statb.st_size;
138 rrd_file->file_len = newfile_size;
139 lseek(rrd_file->fd, newfile_size - 1, SEEK_SET);
140 write(rrd_file->fd, "\0", 1); /* poke */
141 lseek(rrd_file->fd, 0, SEEK_SET);
143 #ifdef HAVE_POSIX_FADVISE
144 /* In general we need no read-ahead when dealing with rrd_files.
145 When we stop reading, it is highly unlikely that we start up again.
146 In this manner we actually save time and diskaccess (and buffer cache).
147 Thanks to Dave Plonka for the Idea of using POSIX_FADV_RANDOM here. */
148 posix_fadvise(rrd_file->fd, 0, 0, POSIX_FADV_RANDOM);
152 if (rdwr & RRD_READWRITE)
154 if (setvbuf((rrd_file->fd),NULL,_IONBF,2)) {
155 rrd_set_error("failed to disable the stream buffer\n");
161 data = mmap(0, rrd_file->file_len, mm_prot, mm_flags,
162 rrd_file->fd, offset);
164 /* lets see if the first read worked */
165 if (data == MAP_FAILED) {
166 rrd_set_error("mmaping file '%s': %s", file_name,
167 rrd_strerror(errno));
170 rrd_file->file_start = data;
171 if (rdwr & RRD_CREAT) {
172 memset(data, DNAN, newfile_size - 1);
176 if (rdwr & RRD_CREAT)
179 if (rdwr & RRD_COPY) {
180 /* We will read everything in a moment (copying) */
181 madvise(data, rrd_file->file_len, MADV_WILLNEED | MADV_SEQUENTIAL);
183 /* We do not need to read anything in for the moment */
184 madvise(data, rrd_file->file_len, MADV_RANDOM);
185 /* the stat_head will be needed soonish, so hint accordingly */
186 madvise(data, sizeof(stat_head_t), MADV_WILLNEED | MADV_RANDOM);
190 __rrd_read(rrd->stat_head, stat_head_t,
193 /* lets do some test if we are on track ... */
194 if (memcmp(rrd->stat_head->cookie, RRD_COOKIE, sizeof(RRD_COOKIE)) != 0) {
195 rrd_set_error("'%s' is not an RRD file", file_name);
196 goto out_nullify_head;
199 if (rrd->stat_head->float_cookie != FLOAT_COOKIE) {
200 rrd_set_error("This RRD was created on another architecture");
201 goto out_nullify_head;
204 version = atoi(rrd->stat_head->version);
206 if (version > atoi(RRD_VERSION)) {
207 rrd_set_error("can't handle RRD file version %s",
208 rrd->stat_head->version);
209 goto out_nullify_head;
211 #if defined USE_MADVISE
212 /* the ds_def will be needed soonish, so hint accordingly */
213 madvise(data + PAGE_START(offset),
214 sizeof(ds_def_t) * rrd->stat_head->ds_cnt, MADV_WILLNEED);
216 __rrd_read(rrd->ds_def, ds_def_t,
217 rrd->stat_head->ds_cnt);
219 #if defined USE_MADVISE
220 /* the rra_def will be needed soonish, so hint accordingly */
221 madvise(data + PAGE_START(offset),
222 sizeof(rra_def_t) * rrd->stat_head->rra_cnt, MADV_WILLNEED);
224 __rrd_read(rrd->rra_def, rra_def_t,
225 rrd->stat_head->rra_cnt);
227 /* handle different format for the live_head */
229 rrd->live_head = (live_head_t *) malloc(sizeof(live_head_t));
230 if (rrd->live_head == NULL) {
231 rrd_set_error("live_head_t malloc");
234 #if defined USE_MADVISE
235 /* the live_head will be needed soonish, so hint accordingly */
236 madvise(data + PAGE_START(offset), sizeof(time_t), MADV_WILLNEED);
238 __rrd_read(rrd->legacy_last_up, time_t,
241 rrd->live_head->last_up = *rrd->legacy_last_up;
242 rrd->live_head->last_up_usec = 0;
244 #if defined USE_MADVISE
245 /* the live_head will be needed soonish, so hint accordingly */
246 madvise(data + PAGE_START(offset),
247 sizeof(live_head_t), MADV_WILLNEED);
249 __rrd_read(rrd->live_head, live_head_t,
252 __rrd_read(rrd->pdp_prep, pdp_prep_t,
253 rrd->stat_head->ds_cnt);
254 __rrd_read(rrd->cdp_prep, cdp_prep_t,
255 rrd->stat_head->rra_cnt * rrd->stat_head->ds_cnt);
256 __rrd_read(rrd->rra_ptr, rra_ptr_t,
257 rrd->stat_head->rra_cnt);
259 rrd_file->header_len = offset;
260 rrd_file->pos = offset;
264 rrd->stat_head = NULL;
273 #if defined DEBUG && DEBUG > 1
274 /* Print list of in-core pages of a the current rrd_file. */
277 rrd_file_t *rrd_file,
281 /* pretty print blocks in core */
284 ssize_t _page_size = sysconf(_SC_PAGESIZE);
286 off = rrd_file->file_len +
287 ((rrd_file->file_len + _page_size - 1) / _page_size);
291 if (mincore(rrd_file->file_start, rrd_file->file_len, vec) == 0) {
293 unsigned is_in = 0, was_in = 0;
295 for (off = 0, prev = 0; off < rrd_file->file_len; ++off) {
296 is_in = vec[off] & 1; /* if lsb set then is core resident */
299 if (was_in != is_in) {
300 fprintf(stderr, "%s: %sin core: %p len %ld\n", mark,
301 was_in ? "" : "not ", vec + prev, off - prev);
307 "%s: %sin core: %p len %ld\n", mark,
308 was_in ? "" : "not ", vec + prev, off - prev);
310 fprintf(stderr, "mincore: %s", rrd_strerror(errno));
313 fprintf(stderr, "sorry mincore only works with mmap");
316 #endif /* defined DEBUG && DEBUG > 1 */
319 /* drop cache except for the header and the active pages */
321 rrd_file_t *rrd_file,
324 #if defined USE_MADVISE || defined HAVE_POSIX_FADVISE
325 unsigned long dontneed_start;
326 unsigned long rra_start;
327 unsigned long active_block;
329 ssize_t _page_size = sysconf(_SC_PAGESIZE);
331 #if defined DEBUG && DEBUG > 1
332 mincore_print(rrd_file, "before");
335 /* ignoring errors from RRDs that are smaller then the file_len+rounding */
336 rra_start = rrd_file->header_len;
337 dontneed_start = PAGE_START(rra_start) + _page_size;
338 for (i = 0; i < rrd->stat_head->rra_cnt; ++i) {
341 + rrd->rra_ptr[i].cur_row
342 * rrd->stat_head->ds_cnt * sizeof(rrd_value_t));
343 if (active_block > dontneed_start) {
345 madvise(rrd_file->file_start + dontneed_start,
346 active_block - dontneed_start - 1, MADV_DONTNEED);
348 /* in linux at least only fadvise DONTNEED seems to purge pages from cache */
349 #ifdef HAVE_POSIX_FADVISE
350 posix_fadvise(rrd_file->fd, dontneed_start,
351 active_block - dontneed_start - 1,
352 POSIX_FADV_DONTNEED);
355 dontneed_start = active_block;
356 /* do not release 'hot' block if update for this RAA will occur
357 * within 10 minutes */
358 if (rrd->stat_head->pdp_step * rrd->rra_def[i].pdp_cnt -
359 rrd->live_head->last_up % (rrd->stat_head->pdp_step *
360 rrd->rra_def[i].pdp_cnt) < 10 * 60) {
361 dontneed_start += _page_size;
364 rrd->rra_def[i].row_cnt * rrd->stat_head->ds_cnt *
368 madvise(rrd_file->file_start + dontneed_start,
369 rrd_file->file_len - dontneed_start, MADV_DONTNEED);
371 #ifdef HAVE_POSIX_FADVISE
372 posix_fadvise(rrd_file->fd, dontneed_start,
373 rrd_file->file_len - dontneed_start, POSIX_FADV_DONTNEED);
375 #if defined DEBUG && DEBUG > 1
376 mincore_print(rrd_file, "after");
378 #endif /* without madvise and posix_fadvise ist does not make much sense todo anything */
386 rrd_file_t *rrd_file)
391 ret = msync(rrd_file->file_start, rrd_file->file_len, MS_ASYNC);
393 rrd_set_error("msync rrd_file: %s", rrd_strerror(errno));
394 ret = munmap(rrd_file->file_start, rrd_file->file_len);
396 rrd_set_error("munmap rrd_file: %s", rrd_strerror(errno));
398 ret = close(rrd_file->fd);
400 rrd_set_error("closing file: %s", rrd_strerror(errno));
407 /* Set position of rrd_file. */
410 rrd_file_t *rrd_file,
417 if (whence == SEEK_SET)
419 else if (whence == SEEK_CUR)
420 rrd_file->pos += off;
421 else if (whence == SEEK_END)
422 rrd_file->pos = rrd_file->file_len + off;
424 ret = lseek(rrd_file->fd, off, whence);
426 rrd_set_error("lseek: %s", rrd_strerror(errno));
429 /* mimic fseek, which returns 0 upon success */
430 return ret < 0; /*XXX: or just ret to mimic lseek */
434 /* Get current position in rrd_file. */
436 inline off_t rrd_tell(
437 rrd_file_t *rrd_file)
439 return rrd_file->pos;
443 /* Read count bytes into buffer buf, starting at rrd_file->pos.
444 * Returns the number of bytes read or <0 on error. */
446 inline ssize_t rrd_read(
447 rrd_file_t *rrd_file,
455 if (rrd_file->pos > rrd_file->file_len || _cnt == 0) /* EOF */
458 return -1; /* EINVAL */
459 _surplus = rrd_file->pos + _cnt - rrd_file->file_len;
460 if (_surplus > 0) { /* short read */
465 buf = memcpy(buf, rrd_file->file_start + rrd_file->pos, _cnt);
467 rrd_file->pos += _cnt; /* mimmic read() semantics */
472 ret = read(rrd_file->fd, buf, count);
474 rrd_file->pos += ret; /* mimmic read() semantics */
480 /* Write count bytes from buffer buf to the current position
481 * rrd_file->pos of rrd_file->fd.
482 * Returns the number of bytes written or <0 on error. */
484 inline ssize_t rrd_write(
485 rrd_file_t *rrd_file,
493 return -1; /* EINVAL */
494 memcpy(rrd_file->file_start + rrd_file->pos, buf, count);
495 rrd_file->pos += count;
496 return count; /* mimmic write() semantics */
498 ssize_t _sz = write(rrd_file->fd, buf, count);
501 rrd_file->pos += _sz;
507 /* flush all data pending to be written to FD. */
509 inline void rrd_flush(
510 rrd_file_t *rrd_file)
512 if (fdatasync(rrd_file->fd) != 0) {
513 rrd_set_error("flushing fd %d: %s", rrd_file->fd,
514 rrd_strerror(errno));
519 /* Initialize RRD header. */
524 rrd->stat_head = NULL;
527 rrd->live_head = NULL;
528 rrd->legacy_last_up = NULL;
530 rrd->pdp_prep = NULL;
531 rrd->cdp_prep = NULL;
532 rrd->rrd_value = NULL;
536 /* free RRD header data. */
542 if (rrd->legacy_last_up) { /* this gets set for version < 3 only */
543 free(rrd->live_head);
550 free(rrd->live_head);
551 free(rrd->stat_head);
557 free(rrd->rrd_value);
562 /* routine used by external libraries to free memory allocated by